The packaging and transportation of products which can flow (in particular liquid products) has always been an awkward problem.
Although the transportation of pulverulent products can be made by other means, the invention provides an advantageous alternative.
Metal and glass containers are used much less than in the past: they are generally heavy, they permit few variations in form, and they are relatively expensive. Glass containers are, moreover, breakable which is a major disadvantage. Metal containers are easily deformed, irreversibly if they are dropped.
Thus, for some decades, the use of various containers in plastic materials has become commonplace for the packaging of, inter alia, liquid food products or products for use in industry or in daily life.
So there has been a progressive replacement of all sorts of containers formerly made in glass or metal by containers in plastic materials intended for the same types of use. These new containers permit easier handling and manipulation, in particular because of the reduction of the risks of breakage or of damaging deformation.
A certain number of problems specific to the use of plastic materials for packaging liquid products have appeared over time. Some of these problems are still with us, and the present invention attempts to remedy them.
For reasons of economy, it is desirable for containers in plastic materials to be as light as possible. With this in mind, and starting with forms copied from glass or metal packagings, there has been a progressive evolution of packagings in plastic materials towards forms that are better adapted to the characteristics of the material. These forms have made it possible to optimize resistance to vertical compression, the limit being given by a non-visible and non-permanent deformation of the packaging.
However, most of the forms developed which provided both good resistance to vertical compression and light weight have one major drawback: the ratio between the volume occupied by the spatial requirement of the pack and the volume of liquid product packed is high, and in no case is it close to the optimum value of 1:1. In bottles of teardrop shape, for example, this ratio is generally about 1.5:1 or 2.2:1. This represents a huge loss of volume and considerably increases the costs of packaging, handling, storage and distribution.
Due to their rigidity, most containers in plastic materials also occupy a considerable place in the volume of household or industrial wastes. It is easy to understand why this volume should be reduced as much as possible.
Moreover, packagings in parallelepipedic form have been in daily use for a very long time for packaging solid materials. Cardboard boxes, light and resistant, are particularly appreciated: they permit a good use of space, they are easy to stack and to palletize, and their volume can be reduced after use.
It is also known to use cardboard boxes for packaging liquid products, provided plastic materials have been used to make them waterproof.
In this regard are aware of boxes formed from plastified cardboard, of the brick type, that are utilized for milk, comprising a small quantity of plastic material and occupying, after use, a reduced space in refuse, provided care is taken to flatten them.
These boxes are manufactured on special machines from cardboard sheet. At least one layer of polyethylene, and possibly one layer of another material such as aluminium, are made integral with the cardboard sheet, by sticking together or by other means. This results in one particularly troublesome drawback from the ecological point of view: the materials making up the single composite layer of the packaging cannot be separated by simple means. Thus, they can neither be destroyed selectively by incineration nor recuperated for purposes of recycling. The cardboard itself, being plastified, is rendered rot-proof.
The method of opening boxes of the brick type utilized for milk is as follows: the user must lift a part, which is folded on the top of the box and folded over the sides, and cut off its corner. If the cutting operation is not performed correctly, which often occurs, milk is spilled when the user picks up the brick in order to pour out its contents. No provision is made, after opening, for the possibility of satisfactory reclosing this type of packaging.
For packaging liquid washing agents, packaging formed from a combination of cardboard and sheets of plastic materials which can, in certain cases, be reclosed each time the product is used, has recently been developed.
Particularly, packaging of the brick type for milk described above, whose method of opening is different, has been marketed; a pouring spout, consisting of an injection-moulded component made from polyethylene, is glued to the centre of the upper wall of the box. When using the container for the first time, the consumer must himself pierce a hole in the wall of the packaging, through the spout, thus creating lips which face the inside of the box. Such lips prevent total emptying of milk from the box. As the spout is applied to the outer part of the composite film forming the wall of the packaging, it can become detached due to impact or rough treatment. As with bricks for milk, any recycling of plastic material or of cardboard is impossible. Moreover, stacking and palletization are difficult due to the projecting pouring spout.
Another type of packaging known on the market and provided for liquid washing agents permits easier pouring of the product. This is packaging which consists of a cardboard sheet which has been given the form of a box, in which a sheet of plastic material welded into the form of a bag, is glued at several points. The upper wall of this packaging is manufactured with an off-centre hole. A spout which is integral with the cardboard and with the sheet of plastic material is positioned at the location of the hole provided on the top of the box. Opening, closing and pouring of the product are relatively easy. Nevertheless, it is observed that, in practice, due in particular to the parallelepipedal form of the box, it is also virtually impossible to empty.
Once again, the composents (cardboard and plastic material) are very difficult to dissociate from one another, which is undesirable from an ecological standpoint. Moreover, this type of packaging requires the use of a considerable amount of adhesive. Finally, the problems of stacking and palletization are still not solved.
There is a particular model of this type of packaging which has a large opening provided in the cover. The spout, which is then integral only with the sheet of plastic material, is able to retract into the box via this opening. What frequently happens now is that it moves obliquely and disappears inside the box, from where it is then awkward to recover. The direction of the flow of product is not guaranteed either, on pouring.
There is also another particular model of this type of packaging, in which the spout is located in a "cut corner" of the cardboard box. In this case, the resistance of the packaging to vertical compression is diminished.
The packaging mentioned above are not designed in order to be filled via the spout. They must be manufactured and filled by complicated and expensive machines which make the cardboard, apply the plastic material thereto and proceed immediately to filling. In each case, this means that the manufacturer of the packaged product must transport his merchandise in bulk to the premises where the packaging is manufactured or invest in machines for manufacturing and filling the packaging, which involves additional cost.